A particularly relevant use for these optically excited spin currents exploits their ability to transfer angular momentum between two ferromagnetic layers.
This was first demonstrated in an experiment investigating the ultrafast laser induced magnetization dynamics of two ferromagnetic layers separated by a conductive spacer layer [1]}.
A diverse body of research into optically generated spin currents has since arisen [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}.
In recent years it has been shown that novel device functionality can be achieved at the intersection of AOS and optically excited spin currents.
These works focus on systems where an all-optically switchable ferrimagnetic layer is separated by a spacer layer from a ferromagnetic layer.
Depending on the precise composition of the layers, either the spin current coming from the ferromagnet can influence the AOS process [9]}, or the ferromagnet can be switched by the spin current coming from the switchable layer [10]}, [11]}, [12]}.
This last case demonstrates the strength of the spin current generated upon excitation of an all-optically switchable system, and begs the question to what extent this spin current plays a role in the switching mechanism.
